In the fоllоwing pаthwаy, eаch arrоw represents an enzyme-catalyzed reaction: X → Y → Z → A. The product of the pathway, molecule A, binds to the enzyme that converts molecule X to molecule Y at a location separate from its active site; this binding decreases the activity of the enzyme. Molecule X is a(n) [blank1] while molecule A functions as a(n) [blank2].